Minnesota HealthSolutions (MHS) proposes to develop an improved harness tensioning system for motor vehicle child safety seats that aims to reduce the risk that the harness is slack. Motor vehicle crashes are the leading cause of death for American children. A total of 2,412 children aged 8 years or younger died as a result of unintentional motor vehicle traffic crashes from 2007-09 and hundreds of thousands more were injured. Child safety seats are the most effective way to protect young children involved in motor vehicle crashes from serious injury or death. Correctly used child safety seats have proven effective at controlling the child's body in collisions; however, when the child harness is loose, the child's body moves excessively relative to the seat resulting in increased head accelerations and an increased likelihood of head contact with the vehicle's interior surfaces. The tightness of the harness on the child's torso at the onset of the crash is directly related to the amount of head excursion and any slack in the harness results in increased head excursion. Despite the importance of correctly tensioning the harness, it is often under-tensioned. Multiple studies have observed that approximately 60% of child safety seats' harnesses are not tight enough, leaving the child at substantially increased risk of injury or death in the event of a crash. The proposed harness tensioning system aims to prevent the risky condition of under tensioned child safety seat harnesses via a technology intervention that provides better indications to the child seat user and a novel mechanism to maintain harness tension during the trip. Injuries in children, in particular head trauma, during motor vehicle crashes will be reduced by reducing the prevalence of harness under-tensioning. The phase I program will design, build, and bench test a prototype seat with the improved harness system and conduct focus groups with potential users.